The present invention relates to a micro-electro-mechanical device and method including a piezoelectric actuator. More particularly, the present invention relates to a device and method of translating piezoelectric action to another member of the device.
Micro-electro-mechanical systems (MEMS) using piezoelectric actuation are typically actuated by utilizing the d31-coefficient of a piezoelectric layer deposited on a cantilever. By means of electrodes parallel to both a cantilever and a piezoelectric layer, an electrostatic field vertical to the cantilever is applied to the piezoelectric layer. This vertical electrostatic field causes an expansion or a contraction of the piezoelectric layer in the transverse, or horizontal, direction. This causes the cantilever to bend. The bending causes an unanchored end of the cantilever to be vertically translated. An example of this type of a device is shown in U.S. Pat. No. 5,742,377.
Unfortunately, the d31-coefficient utilized in the above-described conventional micro-electro-mechanical systems is typically comparatively small. For typical materials the d33-coefficient is 2 to 5 times greater than the d31-coefficient. U.S. Patent Publication No. 2003/0012545 A1 describes a broad-band variable optic attenuator wherein a cantilever is deflected by means of a piezoelectric actuator arranged between a substrate and the cantilever.
For a number of technological reasons, this arrangement is not appropriate for many micro-electro-mechanical devices.